Thanks one and all..I'm still trying to get there, and I think I am, slowly.. :)
Re condensors, points gap, valve lash etc, all bang on, new parts, no change.
Valves on the money. Re having three coils..I have a good friend who lent them to me, they are og
volvo ones, luckily the car is late enough not to have the armoured cable so it is easy to swap them about. I was thinking along the same lines as Shannon regarding the primary circuit, but as I had replaced everything I was dubious..but there was one thing I had not replaced..the wire itself from the coil to the condensor. I took it off and tested it..it had a fine break under the insulation. I was a happy boy...I think that has sorted out part of the problem, but unfortunately not all of it..took car for a test, got it good and hot, drove it hard and it was bang on. ( I do have the correct heat shield for the carbs btw) Before I took the car out I noticed that the fuel in the clear glass filter was quite yellow, not clear as usual. When I returned, it was clear, but the filter was running out of fuel as before, and a lot of air bubbles were coming into the filter..the level got lower and lower as before. Does this signify water in the fuel or a hole in my fuel line somewhere? maybe both..
I really do appreciate all your thoughts, thanks a lot.